Ttl focusing detector

Abstract

Abstract PURPOSE:To detect the real extent of shifting by detecting the light for a subject to be photographed passed through a photographic lens, detecting the extent of shifting of an image formed through the photographic lens from an expected focal plane, and excluding the influence of on-axis chromatic aberration from the detected extent of shifting. CONSTITUTION:Focus detecting operation is repeated through a focusing optical system to discriminate a focusing state. When the lens is not in focus, a digital code signal regarding the on-axis chromatic aberration is read again out of the ROM in an output circuit 51 on the basis of the relation between a brush BR1 and a code plate CD1 according to newly adjusted photographic distance corresponding to the position of a focusing ring FR, so that the address specification of the ROM varies with the code signal. The chromatic aberration to the newly adjusted photographic distance (magnification) is updated, so distance measuring operation is repeated in this state to use optimum on-axis chromatic aberration as the base of the arithmetic of a defocusing extent, attaining more accurate focusing detection.

Inventors

• 👤 Takeshi Egawa
• 👤 猛 江川
• 👤 Akiyoshi Nakamura
• 👤 昭義 中村
• 👤 Shuzo Matsushita
• 👤 修三 松下

Bibliographic Details